Revert "Removes post-build checks for NSOFF builds."

This reverts commit df50ed884aa269876cb5a38f3011bf9ed1965dd3.

This creates problem with platforms which rely on post_build
phase even if they do not build an NS component (i.e. CS1000)

Signed-off-by: Antonio de Angelis <antonio.deangelis@arm.com>
Change-Id: I0f0a3f32ba212f874d3ddebf00d0753093526046
diff --git a/tfm_ci_pylib/tfm_build_manager.py b/tfm_ci_pylib/tfm_build_manager.py
index aec6138..1c59d95 100644
--- a/tfm_ci_pylib/tfm_build_manager.py
+++ b/tfm_ci_pylib/tfm_build_manager.py
@@ -429,7 +429,6 @@
         if "NSOFF" in i.extra_params:
             build_cfg["nspe_config_template"] = ""
             build_cfg["nspe_cmake_build"] = ""
-            build_cfg["post_build"]=""
 
         return build_cfg